Problem: Simplify the following expression. $ (10 + (10 - 7 \times 9)) \times 6 $
Explanation: $ = (10 + (10 - 63)) \times 6 $ $ = (10 + (-53)) \times 6 $ $ = (10 - 53) \times 6 $ $ = (-43) \times 6 $ $ = -43 \times 6 $ $ = -258 $